print('hello world')
print("hello","world")

a='world'
print("hello,%s" % a)
b='hello'
print("%s,%s" % (b,a))

print('%2d-%02d' % (3, 1))
print('%.2f' % 3.1415926) # 四舍五入的方式

# format()
str='Hello, {0}, 成绩提升了 {1:.1f}%'.format('小明', 17.125)
print(str)

# f-string
r = 2.5
s = 3.14 * r ** 2
print(f'The area of a circle with radius {r} is {s:.2f}') # 变量替换了

name=input("输入你的名字:")
print("hello",name,"!")
